use std::io::{Write, BufWriter}; // https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { ($($r:tt)*) => { let stdin = std::io::stdin(); let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next = move || -> String{ bytes.by_ref().map(|r|r.unwrap() as char) .skip_while(|c|c.is_whitespace()) .take_while(|c|!c.is_whitespace()) .collect() }; input_inner!{next, $($r)*} }; } macro_rules! input_inner { ($next:expr) => {}; ($next:expr,) => {}; ($next:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($next, $t); input_inner!{$next $($r)*} }; } macro_rules! read_value { ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) }; ($next:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($next, $t)).collect::>() }; ($next:expr, chars) => { read_value!($next, String).chars().collect::>() }; ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error")); } fn main() { let out = std::io::stdout(); let mut out = BufWriter::new(out.lock()); macro_rules! puts {($($format:tt)*) => (let _ = write!(out,$($format)*););} input! { t: usize, ns: [(usize, chars); t], } for (n, s) in ns { let mut t = vec![0; n]; for i in 0..n { t[i] = match s[i] { 'o' => 1, 'x' => 2, _ => 0, }; } let mut res = 0; for i in 0..std::cmp::max(2, n) - 2 { let mut f = [0; 3]; for j in 0..3 { f[t[i + j]] += 1; } if f == [1, 2, 0] || f == [0, 3, 0] { res = 1; } } for i in 0..std::cmp::max(3, n) - 3 { let mut f = [0; 3]; for j in 0..4 { f[t[i + j]] += 1; } if f == [3, 1, 0] && t[i] == 0 && t[i + 3] == 0 { res = 1; } } for i in 0..std::cmp::max(4, n) - 4 { let mut f = [0; 3]; for j in 0..5 { f[t[i + j]] += 1; } if f == [3, 2, 0] && t[i] == 1 && t[i + 4] == 1 { res = 1; } } let mut v = vec![]; for i in 0..n { if t[i] == 0 { continue; } if t[i] == 2 { v.clear(); continue; } v.push(i); while v.len() > 2 { v.remove(0); } if v.len() >= 2 && (v[1] - v[0]) % 2 == 0 { res = 1; } } puts!("{}\n", ["X", "O"][res]); } }